British Law Enforcement Agencies Campaign to Employ Biased Facial Recognition Technology

Law enforcement agencies across the UK successfully lobbied to use a face scanning system acknowledged as biased against women, young people, and members of minority ethnic backgrounds, following complaints that a less biased version produced fewer investigative leads.

The Technology in Practice

UK forces utilize the national police database to carry out searches using historical face recognition. This process involves matching a “probe image” of a person of interest against a repository of over 19 million mugshots to find possible hits.

Acknowledged Discrimination

The Home Office conceded last week that the technology was biased. This admission followed a review by the National Physical Laboratory (NPL) found it incorrectly matched people of Black and Asian heritage and females at much greater frequency than white men. The Home Office stated it “took steps on the findings”.

“This raises the issue of whether this technology only becomes useful if users tolerate biases in ethnicity and sex. Convenience is a poor argument for overriding fundamental rights.”

Long-Standing Problem

Official papers reveal that this bias has been recognized for over twelve months. Furthermore, law enforcement lobbied to reverse an earlier ruling that was designed to mitigate the problem.

Police bosses were notified of the algorithmic discrimination in September 2024. The government-ordered laboratory study concluded the system was had a higher probability to produce incorrect matches for photos of females, Black people, and those under 40 years old.

A Reversed Decision

In reaction, the national police leadership body mandated that the confidence threshold required for possible hits be raised to a point where the disparity was significantly reduced.

However, this decision was reversed the next month after forces complained that the adjusted system was generating a lower number of “investigative leads”. Internal records indicate the higher threshold cut the proportion of searches that yielded potential matches from 56% to a mere under 15%.

Severe Disparities

Although the Home Office and NPCC refused to say what threshold is now in operation, the latest NPL study discovered the system could produce false positives for women of Black heritage nearly a hundred times more frequently than for white women at certain settings.

The Home Office commented on these findings: “Our evaluation identified that in a limited set of circumstances the algorithm is has a greater tendency to incorrectly include some population segments in its search results.”

Operational Effectiveness vs. Bias

Outlining the effect of the temporary raise to the system's confidence threshold, the NPCC documents state: “This adjustment significantly reduces the effect of discrimination across protected characteristics of ethnicity, generation and sex but had a substantially detrimental effect on operational effectiveness”. The papers add that forces complained that “a once effective tactic now delivered outcomes of limited benefit”.

Wider Implementation Proposals

Meanwhile, the UK administration has launched a ten-week consultation on its proposals to widen the use of facial recognition technology. Policing minister Sarah Jones has described the tool as the “most significant advance since genetic fingerprinting”.

Criticism from Advisors and Monitors

Abimbola Johnson, chair of the advisory panel for the police race action plan, commented: “There was scant consideration in equality strategy sessions of the facial recognition rollout despite obvious cross-over with the strategy's goals.

“This disclosure demonstrate once again that the anti-racism commitments the police has undertaken through the race action plan are failing to be integrated into broader operations. Our reports have cautioned that new technologies are being implemented in a landscape where ethnic inequalities, weak scrutiny and faulty information gathering already persist.

“Any use of this technology must adhere to strict national standards, be subject to external review, and demonstrate it diminishes rather than exacerbates racial disparity.”

Home Office Response

A government representative stated: “The Home Office takes the findings of the report with utmost gravity and we have implemented changes. A updated software has been independently tested and acquired, which has demonstrated no measurable discrimination. It will be tested in the coming months and will be undergo evaluation.

“The foremost aim is protecting the public. This revolutionary tool will assist police to apprehend and prosecute offenders. There is officer review in each stage of the process and no arrest or charge would be taken without trained officers carefully reviewing the output.”